// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Defines a simple integer rectangle class.  The containment semantics
// are array-like; that is, the coordinate (x, y) is considered to be
// contained by the rectangle, but the coordinate (x + width, y) is not.
// The class will happily let you create malformed rectangles (that is,
// rectangles with negative width and/or height), but there will be assertions
// in the operations (such as Contains()) to complain in this case.

#ifndef UI_GFX_GEOMETRY_RECT_H_
#define UI_GFX_GEOMETRY_RECT_H_

#include <cmath>
#include <iosfwd>
#include <string>

#include "base/numerics/safe_conversions.h"
#include "build/build_config.h"
#include "ui/gfx/geometry/point.h"
#include "ui/gfx/geometry/size.h"
#include "ui/gfx/geometry/vector2d.h"

#if defined(OS_WIN)
typedef struct tagRECT RECT;
#elif defined(OS_MACOSX)
typedef struct CGRect CGRect;
#endif

namespace gfx {

class Insets;

class GFX_EXPORT Rect {
public:
    Rect() { }
    Rect(int width, int height)
        : size_(width, height)
    {
    }
    Rect(int x, int y, int width, int height)
        : origin_(x, y)
        , size_(width, height)
    {
    }
    explicit Rect(const Size& size)
        : size_(size)
    {
    }
    Rect(const Point& origin, const Size& size)
        : origin_(origin)
        , size_(size)
    {
    }

#if defined(OS_WIN) || defined(OS_LINUX_FOR_WIN)
    explicit Rect(const RECT& r);
#elif defined(OS_MACOSX)
    explicit Rect(const CGRect& r);
#endif

    ~Rect()
    {
    }

#if defined(OS_WIN) || defined(OS_LINUX_FOR_WIN)
    // Construct an equivalent Win32 RECT object.
    RECT ToRECT() const;
#elif defined(OS_MACOSX)
    // Construct an equivalent CoreGraphics object.
    CGRect ToCGRect() const;
#endif

    int x() const
    {
        return origin_.x();
    }
    void set_x(int x) { origin_.set_x(x); }

    int y() const { return origin_.y(); }
    void set_y(int y) { origin_.set_y(y); }

    int width() const { return size_.width(); }
    void set_width(int width) { size_.set_width(width); }

    int height() const { return size_.height(); }
    void set_height(int height) { size_.set_height(height); }

    const Point& origin() const { return origin_; }
    void set_origin(const Point& origin) { origin_ = origin; }

    const Size& size() const { return size_; }
    void set_size(const Size& size) { size_ = size; }

    int right() const { return x() + width(); }
    int bottom() const { return y() + height(); }

    Point top_right() const { return Point(right(), y()); }
    Point bottom_left() const { return Point(x(), bottom()); }
    Point bottom_right() const { return Point(right(), bottom()); }

    Vector2d OffsetFromOrigin() const { return Vector2d(x(), y()); }

    void SetRect(int x, int y, int width, int height)
    {
        origin_.SetPoint(x, y);
        size_.SetSize(width, height);
    }

    // Shrink the rectangle by a horizontal and vertical distance on all sides.
    void Inset(int horizontal, int vertical)
    {
        Inset(horizontal, vertical, horizontal, vertical);
    }

    // Shrink the rectangle by the given insets.
    void Inset(const Insets& insets);

    // Shrink the rectangle by the specified amount on each side.
    void Inset(int left, int top, int right, int bottom);

    // Move the rectangle by a horizontal and vertical distance.
    void Offset(int horizontal, int vertical);
    void Offset(const Vector2d& distance) { Offset(distance.x(), distance.y()); }
    void operator+=(const Vector2d& offset);
    void operator-=(const Vector2d& offset);

    Insets InsetsFrom(const Rect& inner) const;

    // Returns true if the area of the rectangle is zero.
    bool IsEmpty() const { return size_.IsEmpty(); }

    // A rect is less than another rect if its origin is less than
    // the other rect's origin. If the origins are equal, then the
    // shortest rect is less than the other. If the origin and the
    // height are equal, then the narrowest rect is less than.
    // This comparison is required to use Rects in sets, or sorted
    // vectors.
    bool operator<(const Rect& other) const;

    // Returns true if the point identified by point_x and point_y falls inside
    // this rectangle.  The point (x, y) is inside the rectangle, but the
    // point (x + width, y + height) is not.
    bool Contains(int point_x, int point_y) const;

    // Returns true if the specified point is contained by this rectangle.
    bool Contains(const Point& point) const
    {
        return Contains(point.x(), point.y());
    }

    // Returns true if this rectangle contains the specified rectangle.
    bool Contains(const Rect& rect) const;

    // Returns true if this rectangle intersects the specified rectangle.
    // An empty rectangle doesn't intersect any rectangle.
    bool Intersects(const Rect& rect) const;

    // Computes the intersection of this rectangle with the given rectangle.
    void Intersect(const Rect& rect);

    // Computes the union of this rectangle with the given rectangle.  The union
    // is the smallest rectangle containing both rectangles.
    void Union(const Rect& rect);

    // Computes the rectangle resulting from subtracting |rect| from |*this|,
    // i.e. the bounding rect of |Region(*this) - Region(rect)|.
    void Subtract(const Rect& rect);

    // Fits as much of the receiving rectangle into the supplied rectangle as
    // possible, becoming the result. For example, if the receiver had
    // a x-location of 2 and a width of 4, and the supplied rectangle had
    // an x-location of 0 with a width of 5, the returned rectangle would have
    // an x-location of 1 with a width of 4.
    void AdjustToFit(const Rect& rect);

    // Returns the center of this rectangle.
    Point CenterPoint() const;

    // Becomes a rectangle that has the same center point but with a size capped
    // at given |size|.
    void ClampToCenteredSize(const Size& size);

    // Splits |this| in two halves, |left_half| and |right_half|.
    void SplitVertically(Rect* left_half, Rect* right_half) const;

    // Returns true if this rectangle shares an entire edge (i.e., same width or
    // same height) with the given rectangle, and the rectangles do not overlap.
    bool SharesEdgeWith(const Rect& rect) const;

    // Returns the manhattan distance from the rect to the point. If the point is
    // inside the rect, returns 0.
    int ManhattanDistanceToPoint(const Point& point) const;

    // Returns the manhattan distance between the contents of this rect and the
    // contents of the given rect. That is, if the intersection of the two rects
    // is non-empty then the function returns 0. If the rects share a side, it
    // returns the smallest non-zero value appropriate for int.
    int ManhattanInternalDistance(const Rect& rect) const;

    std::string ToString() const;

    bool ApproximatelyEqual(const Rect& rect, int tolerance) const;

private:
    gfx::Point origin_;
    gfx::Size size_;
};

inline bool operator==(const Rect& lhs, const Rect& rhs)
{
    return lhs.origin() == rhs.origin() && lhs.size() == rhs.size();
}

inline bool operator!=(const Rect& lhs, const Rect& rhs)
{
    return !(lhs == rhs);
}

GFX_EXPORT Rect operator+(const Rect& lhs, const Vector2d& rhs);
GFX_EXPORT Rect operator-(const Rect& lhs, const Vector2d& rhs);

inline Rect operator+(const Vector2d& lhs, const Rect& rhs)
{
    return rhs + lhs;
}

GFX_EXPORT Rect IntersectRects(const Rect& a, const Rect& b);
GFX_EXPORT Rect UnionRects(const Rect& a, const Rect& b);
GFX_EXPORT Rect SubtractRects(const Rect& a, const Rect& b);

// Constructs a rectangle with |p1| and |p2| as opposite corners.
//
// This could also be thought of as "the smallest rect that contains both
// points", except that we consider points on the right/bottom edges of the
// rect to be outside the rect.  So technically one or both points will not be
// contained within the rect, because they will appear on one of these edges.
GFX_EXPORT Rect BoundingRect(const Point& p1, const Point& p2);

inline Rect ScaleToEnclosingRect(const Rect& rect,
    float x_scale,
    float y_scale)
{
    if (x_scale == 1.f && y_scale == 1.f)
        return rect;
    // These next functions cast instead of using e.g. ToFlooredInt() because we
    // haven't checked to ensure that the clamping behavior of the helper
    // functions doesn't degrade performance, and callers shouldn't be passing
    // values that cause overflow anyway.
    DCHECK(base::IsValueInRangeForNumericType<int>(
        std::floor(rect.x() * x_scale)));
    DCHECK(base::IsValueInRangeForNumericType<int>(
        std::floor(rect.y() * y_scale)));
    DCHECK(base::IsValueInRangeForNumericType<int>(
        std::ceil(rect.right() * x_scale)));
    DCHECK(base::IsValueInRangeForNumericType<int>(
        std::ceil(rect.bottom() * y_scale)));
    int x = static_cast<int>(std::floor(rect.x() * x_scale));
    int y = static_cast<int>(std::floor(rect.y() * y_scale));
    int r = rect.width() == 0 ? x : static_cast<int>(std::ceil(rect.right() * x_scale));
    int b = rect.height() == 0 ? y : static_cast<int>(std::ceil(rect.bottom() * y_scale));
    return Rect(x, y, r - x, b - y);
}

inline Rect ScaleToEnclosingRect(const Rect& rect, float scale)
{
    return ScaleToEnclosingRect(rect, scale, scale);
}

inline Rect ScaleToEnclosedRect(const Rect& rect,
    float x_scale,
    float y_scale)
{
    if (x_scale == 1.f && y_scale == 1.f)
        return rect;
    DCHECK(base::IsValueInRangeForNumericType<int>(
        std::ceil(rect.x() * x_scale)));
    DCHECK(base::IsValueInRangeForNumericType<int>(
        std::ceil(rect.y() * y_scale)));
    DCHECK(base::IsValueInRangeForNumericType<int>(
        std::floor(rect.right() * x_scale)));
    DCHECK(base::IsValueInRangeForNumericType<int>(
        std::floor(rect.bottom() * y_scale)));
    int x = static_cast<int>(std::ceil(rect.x() * x_scale));
    int y = static_cast<int>(std::ceil(rect.y() * y_scale));
    int r = rect.width() == 0 ? x : static_cast<int>(std::floor(rect.right() * x_scale));
    int b = rect.height() == 0 ? y : static_cast<int>(std::floor(rect.bottom() * y_scale));
    return Rect(x, y, r - x, b - y);
}

inline Rect ScaleToEnclosedRect(const Rect& rect, float scale)
{
    return ScaleToEnclosedRect(rect, scale, scale);
}

// This is declared here for use in gtest-based unit tests but is defined in
// the gfx_test_support target. Depend on that to use this in your unit test.
// This should not be used in production code - call ToString() instead.
void PrintTo(const Rect& rect, ::std::ostream* os);

} // namespace gfx

#endif // UI_GFX_GEOMETRY_RECT_H_
